Early Warning Strategies and Practices Along the River Rhine

Abstract

In 1986, the International Commission for the Protection of the Rhine (ICPR) installed a Warning and Alarm Plan (WAP) in order to avert the dangers and to detect and investigate the causes of incidental pollution (spills, industrial or shipping accidents). Since then, the number of reported incidents has decreased considerably. The WAP approach is both emission- and immission-based. Within the former, incidents are directly reported by the discharger; within the latter, early warning monitoring systems provide (semi-)continuous measurements of water quality from which unreported spills can be deduced and traced. Both the water authorities and drinking water companies operate such systems, in which various chemical screening techniques are used in combination with biological early warning systems. This two-way strategy, using sensitive equipment, is considered to be best for a river such as the Rhine, as it has a large flow and there is an endless spectrum of chemicals potentially being used and produced within its catchment area. Future improvements in the WAP will focus on information exchange and the use of internationally available “expert” knowledge, the embedding of biological alarms, and a new system of guidance values. The future challenges for early warning monitoring systems include a broadening of analytical and effect windows, and standardization with a better understanding of relations between substance and effect. In a good early warning system, a balance should be sought between effectiveness for the specific river situations, manageability of the WAP-type system, robustness, and cost. Along the Rhine this message is well understood.